Address Unicode license updates

This email was sent by @McCoySmith to the SPDX list https://lists.spdx.org/g/Spdx-legal/message/3593

> Unicode-TOU
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> McCoy Smith via lists.spdx.org
> 12:47 AM (7 hours ago)
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> All:
>
> Unicode recently revised and published its TOUs. See here:
> https://www.unicode.org/copyright.html
>
> The prior TOUs received at SPDX identifier
> (https://spdx.org/licenses/Unicode-TOU.html) so at a minimum there
> probably should be a change to the text associated with that identifier.
>
> However, the TOUs maybe now don't qualify as a license in a way that
> would make them something that SPDX would want to identify. And the old
> TOUs aren't likely something that would be used with anything now given
> they governed the Unicode website and content which now are governed by
> new TOUs.
>
> Might it make sense given this change to just jettison the Unicode-TOU
> identifier altogether?
>
> I'll leave it up to the legal team to figure out how to handle that
> situation, but just a suggestion to perhaps cut back on the size of the
> identifier list?
>
> McCoy
>
> [FWIW, I represent Unicode so will respond to questions on behalf of
> them if needed]

We need to review and update license detection for all these licenses. Historically Unicode licenses, ToU and related have been relatively messy

We have already the updated https://scancode-licensedb.aboutcode.org/unicode-v3.html but Unicode project tend also to customize the text in each project, for instance https://github.com/unicode-org/icu4x/blob/main/LICENSE text is slightly different.

Also we will not deprecate ToU if SPDX decides to do so, because these are seen in the wild.